Paper sheet conveying apparatus

ABSTRACT

A paper sheet conveying apparatus has a conveying belt which moves and conveys a paper sheet, a detection sensor which detects the amount of displacement of the conveying belt from a reference position while moving, and a control device which drives the conveying belt at a low speed when a new device is installed as a conveying belt and initially started up, and after the low-speed driving, variably controls the speed of the conveying belt based on the amount of displacement of the conveying belt detected by the detection sensor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromprior Japanese Patent Application No. 2005-269985, filed Sep. 16, 2005,the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a paper sheet conveying apparatus usedin a paper money processing machine, for example.

2. Description of the Related Art

A paper money processing machine sets paper money in a take-out unit,takes out and conveys the set paper money one by one through a conveyingbelt, judges the kind, front/back, true/false, and normal/damaged of theconveyed paper money by a judgment device, classifies the paper moneyaccording to the results of judgment, and stacks the paper money in aplurality of stacking box.

A paper money processing machine, particularly, a large-scale machineprocessing at middle and high speeds uses a conveying motor to drive aconveying belt at middle and high speeds. A belt with a relatively lowexpansion rate (difficult to expand) is used as a conveying belt, andstretched over with a strong tension, in order to withstand such drivingat middle and high speeds.

However, a conveying belt is stretched over with such a strong tension,the belt will be accustomed to being tightly stretched when assemblingthe machine or replacing the belt, or after installing a new conveyingbelt.

If a machine operation speed is increased to a normal operation speedimmediately after power is turned on, the conveying belt may movezigzag, come off, or break.

Therefore, in a conventional machine, a release motor is provided inaddition to a conveying motor. When assembling the machine or replacingthe belt, the operator opens the machine door, and uses the releasemotor to move the conveying belt at a low speed as a test run. By thistest run, the belt is familiarized to the surrounding conditions, andprevented from getting habits. (Refer to Jpn. Pat. Appln. KOKAIPublication No. 2003-276904, for example.)

However, in the past, judgment on whether a conveying belt isfamiliarized depends on the sense and experience of a machine assemblingor maintenance engineer. The judgment is not always correct. Ifmisjudgment occurs, a conveying belt is driven before being familiarizedwith the conveying rollers, causing meandering, coming off, or breaking.This is a problem, particularly in a middle/high speed paper moneyprocessing machine.

Further, the work to familiarize a conveying belt is dangerous, becausea conveying mechanism is operated by opening the machine door.

A conveying belt may also be accustomed to being expanded, when anambient operating temperature is low, or when the belt has not been usedfor a certain period, as well as immediately after assembling themachine, or replacing the belt. In such a case, a test run is often notperformed at startup of operation, and the belt shifts or comes out,causing a paper jam.

When a paper jam occurs, a jammed paper sheet is removed and theconveying belt is re-driven, but in this case, sometimes the belt may begoing to come off. If the conveying belt is re-driven in such acondition, a secondary jam may occur causing a serious, trouble such as,breaking of the belt.

Further, to remove a jammed paper sheet, the operator opens the machinedoor and moves the conveying belt by using the release motor. This isvery dangerous.

Some types of machine turn off power when the door is opened, and permitthe operator to remove a jammed paper sheet by operating a conveyingsystem by a hand knob. However, when the conveying system is long andincludes a plurality of module, there arises a problem that the operatordoes not easily clear a paper jam.

BRIEF SUMMARY OF THE INVENTION

The present invention has been made under the above circumstances.Accordingly, it is an object of the invention to provide a paper sheetconveying apparatus, which is configured to make automatic, safe andquantitative adjustment to familiarize a conveying belt.

According to a first aspect of the invention, there is provided a papersheet conveying apparatus comprising a conveying belt which moves andconveys a paper sheet; a detection device which detects the amount ofdisplacement of the conveying belt from a reference position whilemoving; and a control device which drives the conveying belt at a lowspeed when a new device is installed as a conveying belt and initiallystarted up, and after the low-speed driving, variably controls the speedof the conveying belt based on the amount of displacement detected bythe detection device.

According to a second aspect of the invention, there is provided a papersheet conveying apparatus comprising a conveying belt which moves andconveys a paper sheet; a detection device which detects the amount ofdisplacement of the conveying belt from a reference position whilemoving; a temperature detection device which detects an ambientoperating temperature of the conveying belt; and a control device whichdrives the conveying belt at a low speed when the temperature of theconveying belt at startup of driving detected by the temperaturedetection device is lower than a reference temperature, and after thelow-speed driving, controls the speed of the conveying belt based on theamount of displacement of the conveying belt detected by the detectiondevice.

According to a third aspect of the invention, there is provided a papersheet conveying apparatus comprising a conveying belt which moves andconveys a paper sheet; a detection device which detects the amount ofdisplacement of the conveying belt from a reference position whilemoving; a judgment device which judges whether the conveying belt hasbeen stopped for over a certain period at startup of driving theconveying belt;.and a control device which drives the conveying belt ata low speed when the judgment device judges the conveying belt to havebeen stopped for over a certain period, and after the low-speed driving,controls the speed of the conveying belt based on the amount ofdisplacement of the conveying belt detected by the detection device.

According to a fourth aspect of the invention, there is provided a papersheet conveying apparatus comprising a conveying belt which moves andconveys a paper sheet; a jam detection device which detects a jam of apaper sheet conveyed by the conveying belt; a detection device whichdetects the amount of displacement of the conveying belt from areference position after the paper jam is cleared; a judgment devicewhich judges whether the conveying belt is to be driven based on theamount of displacement of a paper sheet detected by the detectiondevice; and a control device which drives the conveying belt at a lowspeed when the judgment device judges the conveying belt to be driven,and after the low-speed driving, variably controls the speed of theconveying belt based on the amount of displacement detected by thedetection. device.

According to a further aspect of the invention, it is possible to makeautomatic and quantitative adjustment to familiarize a conveying device,at startup of the first drive after a new conveying device is installed,thereby preventing a conveying device from meandering, coming out, andbreaking.

Besides, after a paper jam is cleared, it is possible to determinewhether a conveying device is to be driven, thereby preventing asecondary paper jam.

Moreover, it is possible to notify a replacement period before aconveying device reaches the end of life, thereby preventing a paperjam.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention, andtogether with the general description given above and the detaileddescription of the embodiments given below, serve to explain theprinciples of the invention.

FIG. 1 is an external perspective view of a paper sheet processingapparatus according to a first embodiment of the invention;

FIG. 2 is a plane view showing a conveying belt in the paper sheetprocessing apparatus of FIG. 1;

FIG. 3 is a front view showing the conveying belt of FIG. 2;

FIGS. 4A to 4C are graphs, each showing the amount of displacement ofthe conveying belt of FIG. 2;

FIGS. 5A to 5C are graphs, each showing the amount of displacement ofthe conveying belt of FIG. 2;

FIG. 6 is a block diagram showing a drive control system of theconveying belt of FIG. 2;

FIGS. 7A to 7C are graphs, each showing the amount of displacement ofthe conveying belt of FIG. 6;

FIGS. 8A to 8C are graphs, each showing a rotation speed of a conveyingmotor of the conveying belt of FIG. 6;

FIGS. 9A to 9C are graphs, each showing changes in an ambient operatingtemperature detected by a temperature sensor of FIG. 6;

FIGS. 10A to 10C are graphs, each showing a rotation speed of aconveying motor variable based on the changes in the ambient operatingtemperatures of FIG. 9;

FIG. 11 is a block diagram showing a drive control system of a conveyingbelt according to a second embodiment of the invention;

FIGS. 12A to 12C are graphs, each showing drive states of the conveyingbelt of FIG. 11;

FIGS. 13A to 13C are graphs, each showing the amount of displacement ofthe conveying belt of FIG. 11;

FIG. 14 is a block diagram showing a drive control system of a conveyingbelt according to a third embodiment of the invention;

FIG. 15 is a plane view showing a state that the conveying belt of FIG.14 comes out;

FIGS. 16A to 16C are graphs, each showing changes in a rotation speed ofa conveying motor of FIG. 14; and

FIGS. 17A to 17C are graphs, each showing the amount of displacement ofthe conveying belt of FIG. 14.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, preferred embodiments of the invention will be explained indetail with reference of the accompanying drawings.

FIG. 1 is a schematic diagram showing a paper sheet processing apparatusaccording to an embodiment of the invention.

The paper sheet processing apparatus has a main body 100. The front sideof the main body 100 can be opened and closed by a door 100 a. Atake-out unit 1 is provided on one side within the main body 100. Thetake-out unit 1 is provided with a take-out rotor 8 to take out a stackof paper sheet P one by one sequentially from the top. The paper sheet Ptaken out by the take-out rotor 8 is held and conveyed by a conveyingdevice at a constant speed. The conveying device 2 is provided with aprocessor 3, which performs various processing for the paper sheet P.The take-out side of the processor 3 is branched into first and secondconveying paths 9 and 11. At the branching point, a first sorting gate 4is provided to sort the paper sheet P to the first and second conveyingpaths 9 and 11. The take-out side of the first conveying path 9 isbranched into third and fourth 13 and 14. At the branching point, asecond sorting gate 12 is provided. The third and fourth conveying paths13 and 14 are connected to first and second stacking units 5 a and 5 b,and the second conveying path 11 is connected to a stacking unit 6 forejection.

In the first conveying path 9, an optical sensor 15 is provided to countthe number of passing paper sheets. Each time the optical sensor 15detects 100 sheets, the second sorting gate 12 is operated to sort thepaper sheets to the direction of the first or second stacking unit 5 aor 5 b.

In the above configuration, the paper sheet P taken out from thetake-out unit 1 is conveyed to the processor 3 by the conveying device2, and processed there. Based on the processed information, the firstsorting gate 4 is operated to sort the paper sheet P to the first orsecond conveying path 9 or 11. The paper sheet sorted to the secondconveying path 11 is stacked in the stacking unit 6 for ejection. Thepaper sheet P sorted to the second conveying path 9 is set to the firststacking unit 5 a through the third conveying path 13, and stackedthere. When 100 sheets are stacked in the first stacking unit 5 a, thesecond sorting gate is operated to send the paper sheet P to the secondstacking unit 5 b through the fourth conveying path 14, and stackedthere. The paper sheets P stacked in the first and second stacking units5 a and 5 b are stacked again as a bundle. Likewise, the paper sheetstacked in the stacking unit 6 for ejection is stacked as a bundle.

FIG. 2 is a plane view showing the above-mentioned conveying device 2.FIG. 3 is a front view of the conveying device.

The conveying device 2 has a pair of conveying belts 21 a and 21 bprovided parallel with a predetermined space. The conveying belts 21 aand 21 b are extended over conveying rollers 22. The conveying roller 22is rotatably fixed to a support shaft 23. The support shaft 23 is fixedto a unit frame 24. The conveying roller 22 is driven by a conveyingmotor 25. The conveying belts 21 a and 21 b are moved by the rotation ofthe motor.

In the vicinity of the conveying belts 21 a and 21 b, a detection sensor27 is provided as a detection device to detect the amount ofdisplacement of the belts while moving. The detection sensor 27 detectsthe amount of displacement of the conveying belts 21 a and 21 b whilemoving, as shown in FIG. 4 and FIG. 5.

FIG. 4A shows the state that the amount of displacement of one conveyingbelt 21 a is large. FIG. 4B shows the state that the amount ofdisplacement of the conveying belt 21 a is improved. FIG. 4C shows thestate that the amount of displacement of the conveying belt 21 a fallswithin given limits and the belt is stabilized.

FIG. 5A shows the state that the amount of displacement of the otherconveying belt 21 b is large. FIG. 5B shows the state that the amount ofdisplacement of the conveying belt 21 b is improved. FIG. 5C shows thestate that the amount of displacement of the conveying belt 21 b fallswithin given limits and the belt is stabilized.

FIG. 6 shows the drive control system of the conveying system configuredas described above.

The detection sensor 27 is connected to a control device 29, as acontrol device/a judgment device, through a transmission circuit. Thecontrol device 29 is connected to the conveying motor 25 of theconveying belt 21 a/21 b, and is connected to first and second notifyunits as first and second notify devices, through the control circuit.The control device 29 is also connected to a temperature sensor 28 as atemperature detection device to detect an ambient operating temperatureof the conveying system, and is connected to a low-speed operationswitch 26. The first notify device 30 a notifies an estimated time thatthe amount of displacement of the conveying belts 21 a and 21 b fallswithin given limits and the belt is stabilized. The second notify device30 b notifies the states that the amount of displacement of theconveying belts 21 a and 21 b detected by the detection sensor 27, orthe amount of displacement of the conveying belts 21 a and 21 b, is overa predetermined value, improved, and falls within given limits,respectively. The first and second notify devices 30 a and 30 b makenotification by displaying letters or by sounds.

After assembling the apparatus or after maintenance/replacement of theconveying belt, or when operating at a low temperature or whenrestarting after stopping the conveying belt for a certain period, thecontrol device 29 operates the conveying motor 25 at a low speed for acertain time. After this low-speed operation, the control devicevariably controls the speeds of the conveying motor 25 and the conveyingbelts 21 a and 21 b according to the amount of displacement of theconveying belt 21 detected by the detection sensor 27, as describedlater in detail.

Explanation will known be given on the operation of the conveying motor25 after assembling the apparatus or after maintenance/replacement ofthe conveying belt, or after installing a new conveying belt.

First, close the door 10 a, and manually depress the low-speed operationswitch 26. The control device 29 operates the conveying motor 25 at alow speed as a trial run, and gradually increases the speed bymonitoring the positions, displacement and meandering of the conveyingbelts 21 a and 21 b through the detection sensor 27, and makes automaticand quantitative adjustment to familiarize the conveying belt to theconveying system.

Namely, after the conveying belts 21 a and 21 b are moved at a low speedby the conveying motor 25, the amount of displacement of the conveyingbelts 21 a and 21 b is detected by the detection sensor 27. In thistime, when the amount of displacement of the conveying belt 21 b islarge, for example, as shown in FIG. 7A, the control device 29 controlsthe speed of the conveying motor 25 to a low speed, as shown in FIG. 8A.As the amount of displacement of the conveying belt 21 b is improved asshown in FIG. 7B by this low-speed operation, the speed of the conveyingmotor 25 is increased as shown in FIG. 8B. When the amount ofdisplacement of the conveying belt 21 b falls within given limits andthe conveying belt is stabilized by this low-speed operation as shown inFIG. 7C, the speed of the conveying motor 25 is increased to a normaloperation speed as shown in FIG. 8C.

While the conveying belts 21 a and 21 b are moving, the first notifydevice 30 a notifies an estimated time that the amount of displacementof the belts 21 a and 21 b falls within given limits. This estimatedtime is determined based on the past data and the changes in the amountof displacement of the conveying belts 21 a and 21 b detected by thedetection sensor 27.

Further, the second notify device 30 b notifies the amount ofdisplacement of the conveying belts 21 a and 21 b at the present time,for example, the states that the amount of displacement of the conveyingbelts 21 a and 21 b is over a predetermined value, improved, and fallswithin given limits.

Since the adjustment to familiarize the conveying belts 21 a and 21 b tothe conveying system is made automatically and quantitatively asdescribed above, the belts can be securely familiarized with lessvariations, compared with the conventional adjustment by the operator'ssense and experience.

Next, an explanation will be given on the operation of the conveyingmotor 25 in normal operation mode, not immediately after assembling theapparatus or after maintenance/replacement of the conveying belt.

The sensor 28 detects an ambient operating temperature at startup of theconveying motor 25. When the detected temperature is lower than aspecification range as shown in FIG. 9A, operate the conveying motor 30at a low temperature for a certain time as a trial run as shown in FIG.10A.

When the temperature in the machine is increased to higher than thelower limit of a specified ambient temperature range as shown in FIG.9B, gradually increase the speed of the conveying motor 25 as shown inFIG. 10B. When the ambient operating temperature is increased to withina specified range by this operation, increase the speed of the conveyingmotor 25 up to a normal operation speed as shown in FIG. 10C.

In the low temperature state, as described above, a trial run isperformed at a low speed, and the speed is gradually increased, and thestartup motor speed for starting the conveying belt is controlled tooptimum. This prevents displacement or coming off of the conveying belt,and prevents a paper jam.

FIG. 11 is a block diagram showing a drive control system of a conveyingbelt according to a second embodiment of the invention.

The same components as those of the first embodiment are given the samereference numerals, and detailed explanation of the components will beomitted.

In the second embodiment, there are provided a first measuring device 31to measure the time passed after installation of a conveying belt, asecond measuring device 33 to measure a cumulative operating time of theconveying motor 25, and a third notify device 35 as a third notifydevice to notify a replacement period of the conveying belt 21.

In the second embodiment, a replacement period of the conveying belt 21is notified before the life of the belt is expired, based on thecumulative operating time of the conveying motor 25, the time passedafter installation of the conveying belt, and the results of detectionof the amount of displacement of the conveying belt, a paper jam causedby the end of the life of the belt.

For example, as shown in FIG. 2A, the cumulative operating time of theconveying motor 25 and time passed after installation of the conveyingbelt are measured, and if the conveying system is judged not to havebeen operated for a certain period based on the measurement data,automatically operate the conveying motor 25 at a low speed for acertain time, and gradually increase the motor speed, so that the amountof displacement of the conveying belt 21 falls within a specified rangeof UL-UL as shown in FIG. 13A.

When the conveying system has been continuously operated and theconveying belt does not reach the end of its life as shown in FIG. 12B,the amount of displacement of the belt is within the specified range(UL-UL).

However, when the cumulative operating time of the conveying motor 25 islong and the conveying belt 21 is going to reach the end of life asshown in FIG. 12C, the conveying belt 21 expands and largely zigzags asshown in FIG. 13C.

When the life of the conveying belt 21 comes close to the end and theconveying belt 21 largely zigzags, the control device 29 judges ittiming of replacing the belt, and the third notify device 25 notifies toreplace the conveying belt.

According to the second embodiment, when the conveying system has notbeen operated for a certain period, the system is automatically operatedat a low speed as a trial run and the motor speed is graduallyincreased, and the conveying belt is prevented from displacing or comingoff, and a paper jam is prevented.

When the life of the conveying belt comes close to the end, it isnotified to the third notify device 35, and the conveying belt can bereplaced before the life is expired, and a paper jam is prevented.

FIG. 14 is a block diagram showing the drive control system of aconveying belt according to a third embodiment of the invention.

The same components as those of the first embodiment are given the samereference numerals, and detailed explanation of the components will beomitted.

In the third embodiment, there are provided a jam detection sensor 37 asa jam detection device to detect a paper jam, and a display unit 39 todisplay a first paper sheet causing a paper jam.

When a paper jam is detected by the jam detection sensor 37, the controldevice 29 displays a first paper sheet causing a paper jam, in thedisplay unit 39.

The operator watches the display 39, opens the door 100 a of the mainbody, and eliminates the jammed paper sheet. When the door 100 a isopened, the safety switch 41 is turned on, and the power of theconveying roller system is turned off, thereby ensuring the safety.Leave the paper sheets other than the one causing the paper jam stayedon the conveying path as they are, and close the door 100 a. The resetswitch 43 is depressed, and the detection sensor 27 detects the positionof the conveying belt after the paper jam, displacing or coming off, ifany, and issues a corrective instruction, if there is any problem.

When the position of the belt, displacing or coming off is not detectedby the sensor 27, start the conveying belt 21 at a low speed, and conveythe paper sheets stayed on the conveying path to the stacking box, whilechecking the belt for meandering.

When the detection sensor 27 detects that the conveying belt 21 b comesoff after a paper jam, as shown in FIG. 15, the control device 29 doesnot operate the conveying motor 25 as shown in FIG. 16A. If theconveying motor 25 is operated while the conveying belt 21 is coming offor being largely displaced, a serious secondary paper jam may occur, andthe conveying belt 21 may be broken. The conveying motor 25 is notoperated to prevent such a serious trouble.

When the detection sensor 27 detects that the conveying belt 21 does notcome off the roller 22, start the conveying motor 25 at a low speed asshown in FIG. 16B, and gradually increase the speed of the conveyingmotor 25 after the displacement of the conveying belt is improved asshown in FIG. 17B.

When the amount of displacement of the conveying belt 21 falls withgiven limits as shown in FIG. 17C, increase the speed of the conveyingmotor 30 to a normal operation speed as shown in FIG. 16C.

As described hereinbefore, according to the embodiment of the invention,assembling and maintenance of the apparatus can be safely performed withthe door 100 a closed. Besides, the positions, displacement and zigzagmovement of the conveying belts 21 a and 21 b are monitored by thedetection sensor 27. Therefore, the low-speed trial run time and therising curve when increasing the speed can be optimally controlled.

Further, when the apparatus is operated at a low temperature or notoperated for a long time, start of the conveying motor 25 isautomatically controlled to a low speed, and the conveying belts 21 aand 21 b are familiarized to the conveying system. This stabilizes theconveying performance.

Moreover, displacing and meandering of the conveying belts 21 a and 21 bare self-diagnosed, and the maintenance/replacement period is notified.Therefore, the symptoms of coming off of the belt can be previouslycollected, a replacement notice can be issued before the life of thebelt is expired, and a paper jam can be prevented.

If a paper jam should occur, the operator can clear the paper jam simplyby opening the door 100 a, removing a first paper sheet causing the jam,and closing the door 100 a. The operator can automatically startup theapparatus while self-diagnosing the displacement and zigzag movement ofthe belt. This improves the operability.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1. A paper sheet conveying apparatus comprising: a conveying belt whichmoves and conveys a paper sheet; a detection device which detects theamount of displacement of the conveying belt from a reference positionwhile moving; and a control device which drives the conveying belt at alow speed when a new device is installed as a conveying belt andinitially started up, and after the low-speed driving, variably controlsthe speed of the conveying belt based on the amount of displacement ofthe conveying belt detected by the detection device.
 2. The paper sheetconveying apparatus according to claim 1, wherein the control deviceleaves the conveying belt driven at a low speed when the amount ofdisplacement of the conveying belt is over a predetermined value,gradually increases the speed of the conveying belt as the amount ofdisplacement of the conveying belt is decreased, and increases the speedof the conveying belt to a predetermined speed when the amount ofdisplacement of the conveying belt falls within given limits.
 3. Thepaper sheet conveying apparatus according to claim 2, further comprisinga first notify device which notifies an estimated time that the amountof displacement of the conveying belt falls within given limits.
 4. Thepaper sheet conveying apparatus according to claim 3, further comprisinga second notify device which notifies states that the amount ofdisplacement of the conveying belt is over a predetermined value,decreased, and falls within given limits, respectively.
 5. A paper sheetconveying apparatus comprising: a conveying belt which moves and conveysa paper sheet; a detection device which detects the amount ofdisplacement of the conveying belt from a reference position whilemoving; a temperature detection device which detects an ambientoperating temperature of the conveying belt; and a control device whichdrives the conveying belt at a low speed when the temperature of theconveying belt at startup of driving detected by the temperaturedetection device is lower than a reference temperature, and after thelow-speed driving, controls the speed of the conveying belt based on theamount of displacement of the conveying belt detected by the detectiondevice.
 6. The paper sheet conveying apparatus according to claim 5,wherein the control device controls to gradually increase the movingspeed of the conveying belt as the temperature detected by thetemperature detection device is increased, and to increase the movingspeed of the conveying belt to a predetermined speed when thetemperature detected by the temperature detection device becomes apredetermined value.
 7. A paper sheet conveying apparatus comprising: aconveying belt which moves and conveys a paper sheet; a detection devicewhich detects the amount of displacement of the conveying belt from areference position while moving; a judgment device which judges whetherthe conveying belt has been stopped for over a certain period, atstartup of driving the conveying belt; and a control device which drivesthe conveying belt at a low speed when the judgment device judges theconveying belt to have been stopped for over a certain period, and afterthe low-speed driving, controls the speed of the conveying belt based onthe amount of displacement of the conveying belt detected by thedetection device.
 8. The paper sheet conveying apparatus according toclaim 7, further comprising a measuring device which measures acumulative driven time of the conveying belt, and time passed after theinstallation of the conveying belt, wherein the judgment device judgeswhether the conveying belt has been stopped for over a certain time,based on the value measured by the measuring device.
 9. The paper sheetconveying apparatus according to claim 8, further comprising a thirdnotify device which notifies replacement of the conveying belt, based onthe amount of displacement of the paper sheet detected by the detectiondevice, the cumulative driven time of the conveying belt measured by themeasuring device, and the time passed after the installation of theconveying belt.
 10. A paper sheet conveying apparatus comprising: aconveying belt which moves and conveys a paper sheet; a jam detectiondevice which detects a jam of a paper sheet conveyed by the conveyingbelt; a detection device which detects the amount of displacement of theconveying belt from a reference position after the paper jam is cleared;a judgment device which judges whether the conveying belt is to bedriven, based on the amount of displacement of a paper sheet detected bythe detection device; and a control device which drives the conveyingbelt at a low speed, when the judgment device judges the conveying beltto be driven, and after the low-speed driving, variably controls thespeed of the conveying belt based on the amount of displacement detectedby the detection device.